Chinese people have used wind（1）

power

power

for thousands of years.Because of the need of war，Zhang Liang invented the kite.To send messages，Zhuge Kongming invented the sky lantern.To go（2）

abroad

abroad

to do business with foreigners，Zheng He used wind to drive his big ships.
   Wind power is a（3）

clean

clean

resource of energy.Now we use it to make electricity mainly.Wind makes windmills spin（風車旋轉）.When the windmills spin，they make electricjye.aiy.It is said that there are millions of windmills in the world now.Why is wind power so popular？First，it's clean.Windmills don't（4）

pollute

pollute

the environment at all.Second，we can use wind power forever（永久） because there is always wind in nature.
   Some people are afraid that windmills will kill birds.It（5）

used

used

to be true，but it isn't true anymore.Old windmills killed birds（6）

because

because

they spun very fast.New windmills spin slowly，and they aren't dangerous for birds.Some people say building windmills will be（7）

harmful

harmful

to the environment.There is no need to worry about it.As long as（只要） we choose the right places，they won't destroy the environment around.Also，windmills are always in unfrequented（人煙稀少的） places，so their noises can't disturb us at all.
   Wind power is becoming more and more common.So（8）

far

far

，more than 80 countries have used wind power to make electricity.About 2.5 percent of the world's power comes from the wind.